This research proposal has as its objective a study of chronic inhibition of cholinesterase and the consequent effects on the central nervous system. This will be accomplished by the following aproaches: a. Further improvements and developmnt of techniques for studying the biochemical aspects of the cholinergic system will be investigated. b. Normal rats, and rats poisoned with cholinesterase-inhibiting agents will be used to study: 1. the turnover of acetylcholine in discrete parts of the brain, 2. the subcellular locaaization of acetylcholine and cholinesterase, 3. the turnover of norepinephrine and serotonin in discrete parts of the brain, 4. cholinesterase activity in discrete parts of the brain and peripheral tissues.